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We review the current status of Parton Distribution Function (PDF) determinations for unpolarized and longitudinally polarized protons and for unpolarized nuclei, which are probed by high-energy hadronic scattering in perturbative Quantum…

High Energy Physics - Phenomenology · Physics 2020-02-18 Jacob J. Ethier , Emanuele R. Nocera

We show that the parton distribution functions (PDF) described by the statistical model have very interesting physical properties which help to understand the structure of partons. The role of the quark helicity components is emphasized as…

High Energy Physics - Phenomenology · Physics 2015-09-28 Claude Bourrely

We review the nucleon's polarized structure functions from the viewpoint of gauge invariant, nonlocal light-cone operators in QCD. We discuss a systematic treatment of the polarized structure functions and the corresponding parton…

High Energy Physics - Phenomenology · Physics 2017-08-23 J. Kodaira

We present results for the $x$ dependence of the unpolarized, helicity, and transversity isovector quark distributions in the proton using lattice QCD, employing the method of quasi-distributions proposed by Ji in 2013. Compared to a…

High Energy Physics - Lattice · Physics 2016-09-02 Constantia Alexandrou , Krzysztof Cichy , Kyriakos Hadjiyiannakou , Karl Jansen , Fernanda Steffens , Christian Wiese

We have calculated the complete matrix of three-loop helicity-difference (`polarized') splitting functions Delta P_ik^(2), i,k = q,g, in massless perturbative QCD. In this note we briefly discuss some properties of the polarized splitting…

High Energy Physics - Phenomenology · Physics 2014-05-15 A. Vogt , S. Moch , J. A. M. Vermaseren

We discuss the effect of QED corrections in the evolution of polarized parton distributions. We solve the corresponding evolution equations exactly to ${\cal O}(\alpha )$ and ${\cal O}(\alpha_s^2)$ in Mellin $N$-space, extending the…

High Energy Physics - Phenomenology · Physics 2024-10-30 Daniel de Florian , Lucas Palma Conte

This work focuses on applications of perturbative QCD (pQCD) and collinear factorization theorem to hard particle production in nuclear and hadronic collisions at the BNL-RHIC and CERN-LHC colliders. The emphasis is on nuclear parton…

High Energy Physics - Phenomenology · Physics 2014-08-29 Ilkka Helenius

We review the latest progress in lattice QCD calculations of the partonic structure of hadrons. This structure is, in particular, described in terms of $x$-dependent distributions, the simplest of which are the standard parton distribution…

High Energy Physics - Lattice · Physics 2021-10-18 Krzysztof Cichy

The $\rho$ meson polarized generalized parton distribution functions, its structure functions $g_1$ and $g_2$ and its axial form factors ${\tilde G}_{1,2}$ are studied based on a light-front quark model for the first time. Comparing our…

High Energy Physics - Phenomenology · Physics 2019-02-06 Bao-Dong Sun , Yu-Bing Dong

We present a detailed QCD analysis of nucleon structure functions $xF_3 (x, Q^2)$, based on Laplace transforms and Jacobi polynomials approach. The analysis corresponds to the next-to-leading order and next-to-next-to-leading order…

High Energy Physics - Phenomenology · Physics 2016-10-05 S. Mohammad Moosavi Nejad , Hamzeh Khanpour , S. Atashbar Tehrani , Mahdi Mahdavi

We study isovector unpolarized and helicity parton distribution functions (PDF) of the proton within the framework of Large Momentum Effective Theory. We use a gauge ensemble, generated by the MILC Collaboration, with a superfine lattice…

High Energy Physics - Lattice · Physics 2020-10-19 Zhouyou Fan , Xiang Gao , Ruizi Li , Huey-Wen Lin , Nikhil Karthik , Swagato Mukherjee , Peter Petreczky , Sergey Syritsyn , Yi-Bo Yang , Rui Zhang

We revise the relation between Parton Distribution Functions (PDFs) and matrix elements computable from lattice QCD, focusing on the quasi-Parton Distribution Functions (qPDFs) approach. We exploit the relation between PDFs and qPDFs in the…

High Energy Physics - Phenomenology · Physics 2020-01-08 Krzysztof Cichy , Luigi Del Debbio , Tommaso Giani

Following our previous proposal [1], we construct a class of good "lattice cross sections" (LCSs), from which we could study partonic structure of hadrons from ab initio lattice QCD calculations. These good LCSs, on the one hand, can be…

High Energy Physics - Phenomenology · Physics 2018-01-12 Yan-Qing Ma , Jian-Wei Qiu

A QCD analysis of the nuclear parton distributions and structure functions in the NLO is performed by using the world data. By having bounded parton distributions for a nuclear with atomic number A, we can obtain the nuclear structure…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Atashbar Tehrani , Ali N. Khorramian

The parton momentum density distributions in the proton are determined from a next-to-leading order QCD analysis of structure functions measured at HERA and by fixed target experiments. Also included are data on the difference of the up and…

High Energy Physics - Phenomenology · Physics 2011-09-13 M. Botje

Measurements of the diffractive structure function, $F_2^D$, of the proton at HERA are used to extract the partonic structure of the Pomeron. Regge Factorization is tested and is found to describe well the existing data within the selected…

High Energy Physics - Phenomenology · Physics 2011-07-19 Halina Abramowicz , Michael Groys , Aharon Levy

Parton distribution functions (PDFs) are nonperturbative quantities describing the relation between a hadron and quarks and gluons within it. We propose to extract PDFs from QCD global analysis of "data" generated by lattice QCD…

High Energy Physics - Phenomenology · Physics 2018-10-24 Yan-Qing Ma , Jian-Wei Qiu

We show the first results for parton distribution functions within the proton at the physical pion mass, employing the method of quasi-distributions. In particular, we present the matrix elements for the iso-vector combination of the…

We present a detailed study of the helicity-dependent and helicity-independent collinear parton distribution functions (PDFs) of the nucleon, using the quasi-PDF approach. The lattice QCD computation is performed employing twisted mass…

Parton distributions are constructed in a statistical physical picture of the nucleon. The chiral properties of QCD lead to strong relations between quarks and antiquarks distributions and the importance of the Pauli exclusion principle is…

High Energy Physics - Phenomenology · Physics 2007-05-23 Jacques Soffer